Astronomers reveal the largest cosmic explosion ever seen

May 12. (EUROPE PRESS) –

a cosmic explosion more than ten times brighter than any known supernovathe largest ever seen, has been captured by astronomers led by the University of Southampton.

The explosion, known as AT2021lwxhas now lasted for more than three years, compared to most supernovae, which only visibly shine for a few months. It took place almost 8 billion light years away.when the universe was about 6 billion years old, and is still being detected by a network of telescopes.

The researchers, who publish results in ‘Monthly Notices of the Royal Astronomical Society’, believe that the explosion is the result of an immense cloud of gas, possibly thousands of times larger than our sun, which has been violently perturbed by a supermassive black hole. Fragments of the cloud would be engulfed, sending shock waves through its remnants, as well as into a large dusty “doughnut” surrounding the black hole. These types of events are very rare and nothing similar has been observed so far.

Last year, astronomers witnessed the brightest explosion on record: a gamma-ray burst known as GRB 221009A. Although this burst was brighter than AT2021lwx’s, it only lasted a fraction of the time, meaning that the total energy released by AT2021lwx’s burst is much higher.

AT2021lwx was first detected in 2020 by the Zwicky Transient Facility in California, and later by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Hawaii. These facilities monitor the night sky to detect transient objects that rapidly change brightness, indicating cosmic events such as supernovae, as well as to find asteroids and comets. Until now the magnitude of the explosion was unknown.

“We discovered it by chance, as our search algorithm flagged it when we were looking for a type of supernova,” he explains. it’s a statement Philip Wiseman, a researcher at the University of Southampton who led the research. Most supernovae and tidal disturbances only last a couple of months before fading out. For something to shine for more than two years was immediately very unusual.”

The team continued to investigate the object with several different telescopes: the Neil Gehrels Swift Telescope (a collaboration between NASA, the UK and Italy), the New Technologies Telescope (operated by the European Southern Observatory) in Chile, and the Large Telescope Canaries on La Palma.

By analyzing the spectrum of light, dividing it into different wavelengths and measuring the different absorption and emission characteristics of the spectrum, the team was able to measure the distance to the object.

“Once you know the distance to the object and how bright it appears to us, you can calculate the brightness of the object at its source. Once those calculations were done, we realized that it is extremely bright.” says Professor Sebastian Hönig, from the University of Southampton, co-author of the research.

The only objects in the universe as bright as AT2021lwx are quasars, supermassive black holes with a constant stream of gas falling on them at high speeds.

Professor Mark Sullivan, also from the University of Southampton and another of the co-authors of the paper, explains that “in a quasar, we see that the brightness increases and decreases over time. But if we look back a decade AT2021lwx had not been detected, and suddenly appears as bright as the brightest things in the universe, which is unprecedented.”

There are different theories as to what could have caused such an explosion, but the Southampton-led team believe the most likely explanation is an extremely large cloud of gas (mostly hydrogen). or dust that has deviated from its orbit around the black hole and has been ejected inward.

The team is now set to collect more data on the explosion, measuring different wavelengths, including X-rays, which could reveal the object’s surface and temperature, as well as underlying processes. They will also carry out enhanced computer simulations to see if they agree with his theory about the cause of the explosion.

Dr. Philip Wiseman predicts that “with new facilities such as the Vera Rubin Observatory’s Legacy Survey of Space and Time coming online in the coming years, we hope to discover more events like this and learn more about Earth’s evolution.” “.